Add insert_tcp_options() nasl function

[jjnicola]

What:
This add support for inserting MSS, Wscale, sack permit and timestamp
tcp options.

Why:
It was not supported and was required.

How:
Run the nasl script below, and check with tcpdump or wireshark that the options are set as expected.

openvas-nasl -X -d -i /<install-prefix>/var/lib/openvas/plugins -t <IPV4 or IPv6 to test the funcs> this_script.nasl

if(description) {
  script_oid("1.2.3");
  exit(0);
}

include("misc_func.inc");

myhost = this_host();
port = 22022;
srcport= 35000;
dstip = get_host_ip();
filter = string("tcp and src ", dstip, " and dst ", myhost, " and dst port ", srcport, " and src port ", port);

ip = forge_ip_packet(ip_v   : 4,
                     ip_hl  : 5,
                     ip_tos : 0,
                     ip_len : 20,
                     ip_id  : rand(),
                     ip_p   : IPPROTO_TCP,
                     ip_ttl : 255,
                     ip_off : 0,
                     ip_src : myhost,
                     ip_dst: dstip);


tcp = forge_tcp_packet(ip       : ip,
                       th_ack   : 0,
                       th_dport : port,
                       th_flags : TH_SYN,
                       #th_seq   : tcp_seq + 1024,
                       th_sport : srcport,
                       th_x2    : 0,
                       th_off   : 5,
                       th_win   : 1024,
                       th_urp   : 0,
                       data:"Hola mundo");

display("TCP options:");
display("TCPOPT_SACK_PERMITTED: ", TCPOPT_SACK_PERMITTED);
display("TCPOPT_MAXSEG: ", TCPOPT_MAXSEG);        
display("TCPOPT_WINDOW: ", TCPOPT_WINDOW);        
display("TCPOPT_TIMESTAMP: ", TCPOPT_TIMESTAMP);    

tcp = insert_tcp_options(tcp:tcp,
                                TCPOPT_MAXSEG, 1024,
                                TCPOPT_WINDOW, 14 ,
                                TCPOPT_SACK_PERMITTED,
                                TCPOPT_TIMESTAMP, 123456, 987654);

r = send_packet(tcp, pcap_active:TRUE, pcap_filter:filter);

## IPv6 Check
IP6_v = 0x06;
IP6_P = IPPROTO_TCP;
IP6_HLIM = 0x40;

ip6_packet = forge_ipv6_packet( ip6_v:IP6_v,
                                ip6_p:IP6_P,
                                ip6_hlim:IP6_HLIM,
                                ip6_src:myhost,
                                ip6_dst:dstip );
                                
tcp6 = forge_tcp_v6_packet(ip6 : ip6_packet,
                           th_dport : port,
                           th_flags : TH_SYN,
                           th_sport : srcport,
                           th_x2    : 0,
                           th_win   : 1024,
                           data: "hola mundo");

tcp6 = insert_tcp_v6_options(tcp:tcp6, TCPOPT_WINDOW, 14, TCPOPT_MAXSEG, 1500, TCPOPT_TIMESTAMP, 123456, 2100000);

r = send_v6packet(tcp6, pcap_active:TRUE, pcap_filter:filter);

Checklist:

• Tests
• CHANGELOG Entry

[ArnoStiefvater]

The formatting is bad here. Maybe put the comment above the line so the formatter does not do this.

[ArnoStiefvater]

opts need to be freed here I guess.

[ArnoStiefvater]

bzero and bcopy are deprecated. memset and memcpy should be used instead.

[ArnoStiefvater]

Tested with the supplied scripts and tcpdump. Everything works as expected.

[cfi-gb]

Reviewed the fixes to my review and approved them (only them, not the whole code changes here which i can't approve).